“I think one of the major tenets of this project is to remain authentic,” Kristin Hayter has said of her experimental pop project Lingua Ignota. Heavily inspired by her surroundings in Appalachia and the region’s rich and complicated Christian history, Hayter’s music is disquieting and urgent. She’ll take the stage for two nights in London’s Hackney neighborhood, at a venue called EartH. —Sophie Kemp